The invention relates to a transmitter for reception of an electric signal from an acoustic drum. The transmitter comprises a vibration-sensitive body, which is designed in such a way that it lies on the drumhead, whose undulation it can acquire and record.
It is well known to arrange transmitters or microphones on the body of an instrument in order to receive an electric signal which can be used for the activation of synthesizers or for the conversion of MIDI information (Musical Instrument Digital Interface).
Known transmitters for acoustic drums comprise as a rule a piezoelectric ceramic body, which is attached to the drumhead with a double-sided adhesive tape. The ceramic body exhibits a relatively slight thickness and in general a circular base area. The transmitters usually used acquire waves of the drumhead regardless of their direction. This triggers problems, among other things because rolls on the drumhead in the middle of the drum emit a weak signal amplitude, while rolls near the edge of the drum result in a strong signal amplitude. This is a genuine source of false signals from the transmitter and was the object of electronic corrections in the subsequent amplification circuit. Certainly it was possible in this way to eliminate a great part of the false signals; however this was dependent on the transmitter sensitivity and on the frequency range of the generated signal.
To prevent the transmitter body from being struck by the drumstick, the body is arranged in great proximity to the edge of the drum. Up until now this has also produced the shortest possible wiring to the required plug and socket device, which up to now has been provided in the form of a separated unit underneath the edge of the drum.
By means of shaping of the transmitter body area and by means of its decentralized positioning on the drumhead the transmitter reacts sensitively to all the different undulations as the result of a roll on the drumhead. Such a transmitter is also especially sensitive to decentralized rolls and the undulations generated therewith on the drumhead. A transmitter in oblong shape for a drum is well known from WO 90/03639.
A further transmitter is well known from EP 0 542 706B1. The vibration-sensitive device of that transmitter is oblong in shape. The longitudinal axis of the vibration-sensitive device points towards the middle of the drumhead.
Such a transmitter has the following drawback:
The sound level which a drumstick roll carries out on the drum depends on the location at which the drumstick strikes the drumhead. The sound level is higher, the closer the drumroll is to the edge area of the drumhead. This can be extraordinarily unpleasant and impair the playback of compositions.